The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Known hybrid powertrain architectures can include multiple torque-generative devices including internal combustion engines and non-combustion torque machine(s) that can transfer torque through an output member to a driveline through a power transmission device. A torque machine, e.g., an electric machine operative as a motor or a generator, can generate a torque input to the transmission independently of a torque input from the internal combustion engine. The torque machine may transform vehicle kinetic energy transferred through the driveline to energy that is storable in an energy storage device. A control system monitors various inputs from the vehicle and the operator and provides operational control of the hybrid powertrain, including controlling operating range and gear shifting, controlling the torque-generative devices, and regulating the power interchange among the energy storage device and the torque-generative devices to manage outputs of the transmission to the driveline, including torque and rotational speed.
Known transmission systems deliver mechanical power from the engine and torque machine(s) to the driveline system including fixed final drive gearing, axles and wheels. A known mechanical transmission allows some freedom in engine operation through selection of one of a plurality of fixed gear drive ratios, a neutral selection that allows the engine to operate when the vehicle is stopped, and clutches or a torque converter for smooth transitions between driving ratios and to launch the vehicle from rest. Transmission gear selection allows power from the engine to be delivered to the transmission and driveline with predetermined ratios of torque multiplication and speed reduction, overdrive, and a reverse direction.
A power-split hybrid transmission can use differential gearing to achieve a continuously variable torque and speed ratio between an input member and an output member to the driveline. The differential gearing transfers mechanical power to the torque machine and to the driveline. Known hybrid powertrain systems include a torque machine that provides torque input to a powertrain system at an input member or an output member of a transmission.